amsmath – AMS mathematical facilities for LaTeX

The pack­age pro­vides the prin­ci­pal pack­ages in the
AMS-LaTeX dis­tri­bu­tion. It adapts
for use in LaTeX most of the math­e­mat­i­cal fea­tures found in
AMS-TeX; it is highly rec­om­mendsd as an
ad­junct to se­ri­ous math­e­mat­i­cal type­set­ting in LaTeX.

Ams­math is part of the LaTeX re­quired dis­tri­bu­tion; how­ever,
sev­eral con­tributed pack­ages add still fur­ther to its ap­peal;
ex­am­ples are em­pheq, which pro­vides
func­tions for dec­o­rat­ing and high­light­ing math­e­mat­ics, and
nthe­o­rem, for spec­i­fy­ing the­o­rem
(and sim­i­lar) def­i­ni­tions.